Motion vector obtaining method and apparatus, computer device, and storage medium

Abstract

This application discloses a motion vector obtaining method and apparatus, a computer device, and a storage medium. In the method, an initial motion vector of a to-be-processed picture block is determined by using a location relationship between a reference block and the to-be-processed picture block. When the reference block and the to-be-processed picture block are located in a same coding tree block, a decoder uses an initial motion vector of the reference block as the initial motion vector of the to-be-processed picture block. When the reference block and the to-be-processed picture block are located in different coding tree blocks, the decoder uses a final motion vector of the reference block as the initial motion vector of the to-be-processed picture block.

What is claimed is: 
     
       1. A method for determining motion vector residual, comprising:
 obtaining identification information; 
 obtaining an initial motion vector of a coding unit of a picture based on the identification information; 
 obtaining a plurality of candidate final motion vectors based on the initial motion vector and a plurality of preset offset vectors; 
 obtaining a final motion vector from the plurality of candidate final motion vectors, wherein the final motion vector has a minimum distortion cost amongst the plurality of candidate final motion vectors, wherein the distortion cost is calculated by using a sum of absolute differences; and 
 calculating a difference between the final motion vector and the initial motion vector, wherein the difference represents a motion vector residual of a picture block to be processed, 
 wherein the final motion vector comprises a first forward motion vector and a first backward motion vector, and the initial motion vector comprises a second forward motion vector and a second backward motion vector; the first forward motion vector and the second forward motion vector indicate a motion compensation block based on a first reference frame list of the picture block, the distortion cost of the first forward motion vector is same as that of the first backward motion vector, and the first backward motion vector and the second backward motion vector indicate a motion compensation block based on a second reference frame list of the picture block. 
 
     
     
       2. The method according to  claim 1 , wherein the method is applied for an inter prediction mode. 
     
     
       3. An encoder, comprising:
 at least one processor; and 
 one or more memories coupled to the at least one processor and storing programming instructions, which when executed by the at least one processor, cause the encoder to: 
 obtain identification information; 
 obtain an initial motion vector of a coding unit of a picture based on the identification information; 
 obtain a plurality of candidate final motion vectors based on the initial motion vector and a plurality of preset offset vectors; 
 obtain a final motion vector from the plurality of candidate final motion vectors, wherein the final motion vector has a minimum distortion cost amongst the plurality of candidate final motion vectors, wherein the distortion cost is calculated by using a sum of absolute differences; and 
 calculate a difference between the final motion vector and the initial motion vector, wherein the difference represents a motion vector residual of a picture block to be processed, 
 wherein the final motion vector comprises a first forward motion vector and a first backward motion vector, and the initial motion vector comprises a second forward motion vector and a second backward motion vector; the first forward motion vector and the second forward motion vector indicate a motion compensation block based on a first reference frame list of the picture block, the distortion cost of the first forward motion vector is same as that of the first backward motion vector, and the first backward motion vector and the second backward motion vector indicate a motion compensation block based on a second reference frame list of the picture block. 
 
     
     
       4. The encoder according to  claim 3 , wherein the encoder performs in an inter prediction mode. 
     
     
       5. A coding apparatus, comprising:
 at least one processor; 
 a memory for storing a bitstream having identification information, wherein the identification information is used to obtain an initial motion vector of a coding unit; and 
 an encoder operatively coupled to the memory and configured by the at least one processor to:
 obtain identification information; 
 obtain an initial motion vector of a coding unit of a picture based on the identification information; 
 obtain a plurality of candidate final motion vectors based on the initial motion vector and a plurality of preset offset vectors; 
 obtain a final motion vector from the plurality of candidate final motion vectors, wherein the final motion vector has a minimum distortion cost amongst the plurality of candidate final motion vectors, wherein the distortion cost is calculated by using a sum of absolute differences; and 
 calculate a difference between the final motion vector and the initial motion vector, wherein the difference represents a motion vector residual of a picture block to be processed, 
 wherein the final motion vector comprises a first forward motion vector and a first backward motion vector, and the initial motion vector comprises a second forward motion vector and a second backward motion vector; the first forward motion vector and the second forward motion vector indicate a motion compensation block based on a first reference frame list of the picture block, the distortion cost of the first forward motion vector is same as that of the first backward motion vector, and the first backward motion vector and the second backward motion vector indicate a motion compensation block based on a second reference frame list of the picture block. 
 
 
     
     
       6. The coding apparatus according to  claim 5 , wherein the encoder performs in an inter prediction mode. 
     
     
       7. The method according to  claim 1 ,
 wherein the calculating a difference between the final motion vector and the initial motion vector comprises: 
 calculating a difference between the first forward motion vector and the second forward motion vector as a first motion vector residual of the picture block. 
 
     
     
       8. The method according to  claim 7 , further comprising:
 calculating a difference between the first backward motion vector and the second backward motion vector as a second motion vector residual of the picture block. 
 
     
     
       9. The method according to  claim 7 , further comprising:
 using the first forward motion vector as the first motion vector residual of the picture block. 
 
     
     
       10. The method according to  claim 9 , further comprising:
 using the first backward motion vector as a second motion vector residual of the picture block. 
 
     
     
       11. The encoder according to  claim 3 ,
 wherein the calculate a difference between the final motion vector and the initial motion vector comprises: 
 calculate a difference between the first forward motion vector and the second forward motion vector as a first motion vector residual of the picture block. 
 
     
     
       12. The encoder according to  claim 11 , wherein the programming instructions, which when executed by the at least one processor, cause the encoder further to:
 calculate a difference between the first backward motion vector and the second backward motion vector as a second motion vector residual of the picture block. 
 
     
     
       13. The encoder according to  claim 11 , wherein the programming instructions, which when executed by the at least one processor, cause the encoder further to:
 use the first forward motion vector as the first motion vector residual of the picture block. 
 
     
     
       14. The encoder according to  claim 13 , wherein the programming instructions, which when executed by the at least one processor, cause the encoder further to:
 use the first backward motion vector as a second motion vector residual of the picture block. 
 
     
     
       15. The coding apparatus according to  claim 5 ,
 wherein the calculate a difference between the final motion vector and the initial motion vector comprises: 
 calculate a difference between the first forward motion vector and the second forward motion vector as a first motion vector residual of the picture block. 
 
     
     
       16. The coding apparatus according to  claim 15 , wherein the encoder is configured to:
 calculate a difference between the first backward motion vector and the second backward motion vector as a second motion vector residual of the picture block. 
 
     
     
       17. The coding apparatus according to  claim 15 , wherein the encoder is configured to:
 use the first forward motion vector as the first motion vector residual of the picture block. 
 
     
     
       18. The coding apparatus according to  claim 17 , wherein the encoder is configured to:
 use the first backward motion vector as a second motion vector residual of the picture block.